1. Field of the Invention
The present invention relates to a camera apparatus. In particular, the present invention relates to a camera apparatus with an infrared night vision charge coupled device.
2. Description of the Related Art
FIG. 1 shows a conventional camera apparatus with an infrared night vision charge coupled device. FIG. 2 is a sectional view of the conventional camera apparatus in FIG. 1. The conventional camera apparatus 1 comprises a casing 11, a substantially L-shaped aluminum plate 12 mounted in the casing 11, a light source module 13 mounted on the aluminum plate 12, a shooting module 14 mounted on the aluminum plate 12, and a power supply unit 15 mounted on the aluminum plate 12.
The casing 11 comprises a cylindrical body 111, a fixing ring 112 mounted to a front end of the body 111, a rear cap 113 mounted to a rear end of the body 111, and a transparent glass 115. A rubber gasket or washer 114 is sandwiched between the transparent glass 115 and the fixing ring 112, and another rubber gasket or washer 14 is sandwiched between the rear end of the body 111 and the rear cap 113.
The rear cap 113 includes two through-holes 116 each having an inner threading for threadedly engaging with an outer threading of a coupler 117. Each coupler 117 is covered by a waterproof plastic film (not shown) and screwed to the rear cap 113. However, the waterproof effect between the coupler 117 and the associated through-hole 116 is not satisfactory.
The aluminum plate 12 includes a horizontal section 121 and an upright section 122 extending from the horizontal section 121. The light source module 13 includes an infrared board 131, a plurality of light-emitting diodes (LEDs) 132, and a photosensitive resistor 133. The shooting module 14 includes a charge coupled device circuit board 141 and a lens 142 that is mounted in a central portion of the charge coupled device circuit board 141 and that extends through the vertical section 122 and the infrared board 131 in sequence.
In assembly, the infrared board 131 of the light source module 13 is screwed to two copper pegs 123 on a side of the vertical section 122. The charge coupled device circuit board 141 of the shooting module 14 is screwed to four studs 124 on the other side of the vertical section 122.
The power supply unit 15 includes a transformer 151, an alternating-current power line 152 that is connected between a power source (not shown) and the transformer 151 on the charge coupled device circuit board 141 and that extends through one of the couplers 117 in the associated through-hole 116, and a signal output line 153 that is connected between the charge coupled device circuit board 141 and an electric device (not shown) and that extends through the other couple 117 in the associated through-hole 116. Thus, the alternating-current power line 152 and the signal output line 153 respectively extend through the through-holes 116, preventing the signal output line 153 from being interfered by the alternating-current power line 152. In a case that the environment is not bright enough for shooting, the light source module 13 is activated by the photosensitive resistor 133 to provide additional illumination for shooting purposes. Thus, the shooting module 14 may proceed with shooting even in the night or a dark place.
Since the camera apparatus 1, especially an infrared night vision camera, is usually mounted outdoors for monitoring purposes, the camera apparatus 1 must be completely waterproof. The camera apparatus 1 is often mounted in a high location and inclines forward for shooting downward. However, the transparent glass 115 becomes foggy in the dawn, a rainy day, or foggy hours, the image is thus vague. The camera apparatus 1 must be detached in a case that the moisture cannot be expelled. The waterproof effect is one of the most important issues of the camera apparatus 1.
The fixing ring 112 and the body 111 however have a poor waterproof effect therebetween, as a gap exists between the fixing ring 112 and the body 111 due to the arrangement of the rubber washer 114 and bolts 118 for fixing the fixing ring 112 and the rubber washer 114. The same situation exists between the rear cap 113 and the associated rubber washer 114. Further, since the camera apparatus 1 inclines forward, the water flows easily along the alternating-current power line 152 and the signal output line 153 into the through-holes 116 as well as the casing 11. Also, water may flow via the gaps between the couplers 117 and the rear cap 113, as the couplers 117 are not integrally formed with the rear cap 113 and thus have a poor waterproof effect. Further, the plug for the alternating-current power line 152 and the plug for the signal output line 153 may also be problems, as these plugs are not treated for waterproof purposes, resulting in easy penetration of water into the casing 11. In a case that water enters the power supply unit 15 along the alternating-current power line 152 and/or the signal output line 153, the charge coupled device circuit board 141 and the circuit board of the power supply unit 15 are liable to be damaged.
A further problem of the camera apparatus 1 is heat dissipation. The LEDs 132 and the electronic elements such as drive transistors (not shown), current limiting resistors (not shown), etc on the infrared board 131 generate a considerable amount of heat that are transmitted via the pins of the LEDs 132 or the electronic elements to the infrared board 131. Since the casing 11 is sealed and since the infrared board 131 is made of glassfiber having a poor thermal conductivity, only a small amount of heat is dissipated through the copper pegs 123 to the vertical section 122 of the aluminum plate 12, resulting in high temperature while the light source module 13 is working.
The power supply unit 15 also generates heat while working, which may adversely affect the LEDs 132, the charge coupled device circuit board 141, and the lens 142 having high precision, leading to burning out of the LEDs 132 in a short time, deterioration of precision of the charge coupled device circuit board 141 and the lens, shortening of the life, and malfunctioning of the camera apparatus 1. Also, the heat generated by the light source module 13 adversely affects the function of the power supply unit 15.
In a case of maintenance or repair due to malfunction of any one of the light source module 13, the shooting module 14, and the power supply module 15 is required, the rear cap 113 has to be detached and the aluminum plate 12 is then removed. The power supply unit 15 however malfunctions easily, and the repair is troublesome. Further, the waterproof effect between the rear cap 113 and the body 111 deteriorates every time the rear cap 113 is detached. The ambient moisture enters the casing 11 easily and causes the transparent glass 115 to become foggy, which definitely occurs when the light source module 13 (that may include up to 84 LEDs) generate high heat. The image is thus vague. Repair is inevitable, and what is worse, the charge coupled device is liable to be burned out.